awful cramps. not on period

last week, i was masterbating and i started what i thought was my period. it only lasted that night and there was clots like i normally have. after that night, there was no more blood and i was having horrible cramps the week before that too. I have been having cramps for 3 weeks. everytime i eat i get horrible stomach pain in my lower stomach where i normal get it.and btw i rarely get cramps, only like every few months. why am i experiencing this?? ps. googled it and everything says early pregnancy but I'm a virgin tf